When pressed on the fact that He is dining with “tax collectors and sinners,” Jesus ultimately responds by effectively saying “I came to call sinners.” That is, “these are the people---these tax collectors and sinners (Gentiles and those treated as Gentiles, if you will)---that I intend to gather into the kingdom of the Creator God. I am going after these people.” Concordantly, a regular accusation that would be leveled against Jesus, that was intended (among other things) to show that He could not possibly be Israel’s Messiah, was the manner of His table fellowship and the people with which He surrounded Himself.
In the eleventh chapter of Matthew, recognizing the constant building of the story and the inter-connectivity of the pieces of the narrative, Jesus Himself gives voice to this charge, reporting what it was that was being said about Him: “Look at Him, a glutton and a drunk, a friend of tax collectors and sinners!” (Matthew 11:19b). Surely, the thoughts seemed to run, Israel’s messiah would not surround Himself with those that are taken to be outside of the Creator’s covenant---not displaying or adhering to the accepted and determined covenant markers (circumcision, dietary laws, Sabbath-keeping) of the people of the Creator God. By His consistent fraternization with and acceptance of such people, Jesus demonstrated His attitude towards and compassion for said classes of people, while also providing the example to be followed by all those that would come to cast their lot with Him and His kingdom way.
In a way that seems to run contrary to that which has been seen to this point, in the tenth chapter Jesus can be found sending out His twelve disciples and instructing them “Do not go to Gentile regions and do not enter any Samaritan town. Go instead to the lost sheep of the house of Israel” (10:5b-6). Right along with Matthew’s hearers, any reader of the Gospel should find this to be highly unusual, as it would seem to run counter to what has been seen and heard from Jesus. This can be understood just a bit better upon hearing what it is that is to be the content of their message, which is that “The kingdom of heaven is near!” (10:7b) This is a fundamentally Jewish concept that would not necessarily have been understood by Gentiles and Samaritans. So this instruction by Jesus may need to be understood less as a restriction, and understood more alone the lines of practicality. At the same time, a careful inspection of Matthew seems to reveal that Jesus limits His talk of the kingdom of heaven to His interaction with the people of Israel, which can also serve to make sense of the practical nature of the instructions.
Of course, this tension is held in mind and ultimately balanced by the great commission that will be encountered in the closing verses of Matthew’s Gospel. This tension and expectation of what is to come is played out here in the tenth chapter, as Jesus continues His instructions by saying “I am sending you out like sheep surrounded by wolves… Beware of people, because they will hand you over to councils and flog you in their synagogues” (10:16a,17), which would come to be the experience of the community of Christ-followers in the years following the Christ-event and in the time in which this Gospel would have been composed and shared.
As it relates to understanding what it means to treat someone as a Gentile or tax collector, Jesus relates the greater purpose of this treatment of His disciples, saying “And you will be brought before governors and kings because of me” (10:18a). Here, one cannot help but think of the records of the travails of Peter, John, and Paul and their respective appearances before the authorities (especially those of Paul), which would quite likely have been known to the community for which Matthew has compiled his narrative. When standing before governors and kings, Jesus’ persecuted disciples would act “as a witness to them and the Gentiles” (10:18b). Yes, Jesus was always cognizant of His mission. Accordingly, His church has always been cognizant of its mission. This mission, as Matthew’s hearers would well-know and would routinely hear, included reaching out to Gentiles so as to bring them into the plans and purposes and ever-widening fold of the people of the kingdom of the Creator God.